The corneal epithelium has been implicated in the destruction of either the fibrous and/or protein polysaccharide elements of the corneal stroma. Evidence stems from others' observations of in vivo alkali-burned rabbit corneas and human keratoconus and in vitro cultures and extracts of normal rabbit and calf tissue. The present initiating study will explore biochemically the potential capacity of the epithelium to depolymerize homologous corneal basement membrane and stromal matrix and/or ground substance devoid of viable cells. Which epithelial subcellular entities are responsible and the effect of the variables pH, ionic milieu and potentially effective inhibitors on the susceptibility of the particular substrates to proteolytic attack will be studied.